Feature: get correct next VMID (#4292)

fix(vm-creation): ensure whiptail VMID inputbox is pre-filled with a valid and available ID

- Replaced hardcoded NEXTID usage with a new get_valid_nextid() function
- Ensures no collision with existing VMs, LXCs or orphaned LVM volumes
- Improves user experience by properly pre-filling whiptail inputbox
- Automatically skips invalid IDs instead of failing on alloc

vm/opnsense-vm.sh

@@ -28,7 +28,7 @@ var_version="25.1"
 #
 GEN_MAC=02:$(openssl rand -hex 5 | awk '{print toupper($0)}' | sed 's/\(..\)/\1:/g; s/.$//')
 GEN_MAC_LAN=02:$(openssl rand -hex 5 | awk '{print toupper($0)}' | sed 's/\(..\)/\1:/g; s/.$//')
-NEXTID=$(pvesh get /cluster/nextid)
+
 YW=$(echo "\033[33m")
 BL=$(echo "\033[36m")
 HA=$(echo "\033[1;34m")
@@ -54,6 +54,23 @@ function error_handler() {
   cleanup_vmid
 }
 
+function get_valid_nextid() {
+  local try_id
+  try_id=$(pvesh get /cluster/nextid)
+  while true; do
+    if [ -f "/etc/pve/qemu-server/${try_id}.conf" ] || [ -f "/etc/pve/lxc/${try_id}.conf" ]; then
+      try_id=$((try_id + 1))
+      continue
+    fi
+    if lvs --noheadings -o lv_name | grep -qE "(^|[-_])${try_id}($|[-_])"; then
+      try_id=$((try_id + 1))
+      continue
+    fi
+    break
+  done
+  echo "$try_id"
+}
+
 function cleanup_vmid() {
   if qm status $VMID &>/dev/null; then
     qm stop $VMID &>/dev/null
@@ -202,7 +219,7 @@ function exit-script() {
 }
 
 function default_settings() {
-  VMID="$NEXTID"
+  VMID=$(get_valid_nextid)
   FORMAT=",efitype=4m"
   MACHINE=""
   DISK_CACHE=""
@@ -252,10 +269,11 @@ function default_settings() {
 function advanced_settings() {
   local ip_regex='^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$'
   METHOD="advanced"
+  [ -z "${VMID:-}" ] && VMID=$(get_valid_nextid)
   while true; do
-    if VMID=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Virtual Machine ID" 8 58 $NEXTID --title "VIRTUAL MACHINE ID" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+    if VMID=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Virtual Machine ID" 8 58 $VMID --title "VIRTUAL MACHINE ID" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
       if [ -z "$VMID" ]; then
-        VMID="$NEXTID"
+        VMID=$(get_valid_nextid)
       fi
       if pct status "$VMID" &>/dev/null || qm status "$VMID" &>/dev/null; then
         echo -e "${CROSS}${RD} ID $VMID is already in use${CL}"